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  Subjects -> ENGINEERING (Total: 2054 journals)
    - CHEMICAL ENGINEERING (169 journals)
    - CIVIL ENGINEERING (160 journals)
    - ELECTRICAL ENGINEERING (87 journals)
    - ENGINEERING (1142 journals)
    - ENGINEERING MECHANICS AND MATERIALS (318 journals)
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ENGINEERING (1142 journals)            First | 5 6 7 8 9 10 11 12 | Last

Machining Science and Technology: An International Journal     Hybrid Journal   (Followers: 2)
Macromolecular Reaction Engineering     Hybrid Journal  
Magazine of Concrete Research     Hybrid Journal   (Followers: 6)
Magdeburger Journal zur Sicherheitsforschung     Open Access  
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 3)
Management and Production Engineering Review     Open Access  
Management Science and Engineering     Open Access   (Followers: 1)
Manufacturing Engineer     Hybrid Journal   (Followers: 3)
Manufacturing Research and Technology     Full-text available via subscription   (Followers: 4)
MATEC Web of Conferences     Open Access  
Matériaux & Techniques     Full-text available via subscription   (Followers: 1)
Mathematical Models and Methods in Applied Sciences     Hybrid Journal   (Followers: 2)
Mathematical Problems in Engineering     Open Access   (Followers: 3)
Mathematics of Control, Signals, and Systems (MCSS)     Hybrid Journal   (Followers: 5)
Mauerwerk     Hybrid Journal  
Measurement     Hybrid Journal   (Followers: 1)
Measurement Science Review     Open Access   (Followers: 1)
Meccanica     Hybrid Journal   (Followers: 1)
Mechatronics     Hybrid Journal   (Followers: 4)
Medical and Biological Engineering and Computing     Hybrid Journal   (Followers: 2)
Medical Engineering & Physics     Hybrid Journal   (Followers: 9)
Membrane Science and Technology     Full-text available via subscription   (Followers: 2)
Membrane Technology     Full-text available via subscription   (Followers: 1)
Memetic Computing     Hybrid Journal  
Metal Powder Report     Full-text available via subscription   (Followers: 5)
Metallurgist     Hybrid Journal   (Followers: 2)
Metaphysica     Hybrid Journal   (Followers: 1)
Metascience     Hybrid Journal   (Followers: 1)
Metrologia     Full-text available via subscription   (Followers: 1)
Microelectronic Engineering     Hybrid Journal   (Followers: 4)
Microelectronics International     Hybrid Journal  
Microelectronics Journal     Hybrid Journal   (Followers: 5)
Microelectronics Reliability     Hybrid Journal   (Followers: 6)
Microfluidics and Nanofluidics     Hybrid Journal   (Followers: 9)
Micromachines     Open Access   (Followers: 2)
MNASSA : Monthly Notes of the Astronomical Society of South Africa     Full-text available via subscription   (Followers: 1)
Modelling and Simulation in Engineering     Open Access   (Followers: 4)
Modern Applied Science     Open Access   (Followers: 1)
Molecular BioSystems     Full-text available via subscription   (Followers: 2)
Molecular Engineering     Hybrid Journal  
Molecular Pharmaceutics     Full-text available via subscription   (Followers: 9)
MRS Bulletin     Full-text available via subscription   (Followers: 5)
MRS Online Proceedings     Full-text available via subscription   (Followers: 1)
Multiagent and Grid Systems     Hybrid Journal  
Multidimensional Systems and Signal Processing     Hybrid Journal  
NANO     Hybrid Journal   (Followers: 8)
Nano Letters     Full-text available via subscription   (Followers: 50)
Nano Research     Hybrid Journal   (Followers: 5)
Nano Reviews     Open Access   (Followers: 17)
Nanopages     Full-text available via subscription   (Followers: 1)
Nanoscale and Microscale Thermophysical Engineering     Hybrid Journal   (Followers: 3)
Nanoscale Systems : Mathematical Modeling, Theory and Applications     Open Access  
Nanoscience and Nanoengineering     Open Access  
Nanoscience and Nanotechnology     Open Access   (Followers: 2)
Nanoscience and Nanotechnology Research     Open Access   (Followers: 1)
Nanotechnologies in Russia     Hybrid Journal   (Followers: 1)
Nanotechnology     Hybrid Journal   (Followers: 10)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 15)
Nanotechnology Reviews     Full-text available via subscription   (Followers: 5)
Natural Hazards     Hybrid Journal   (Followers: 287)
Nature Nanotechnology     Full-text available via subscription   (Followers: 48)
Naval Engineers Journal     Hybrid Journal   (Followers: 3)
NDT & E International     Hybrid Journal   (Followers: 14)
Nexo Revista Científica     Open Access  
Nigerian Journal of Technological Research     Full-text available via subscription  
Nigerian Journal of Technology     Full-text available via subscription  
NIR news     Full-text available via subscription  
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
Nonlinear Engineering : Modeling and Application     Full-text available via subscription   (Followers: 1)
Nordic Journal of Science and Technology     Open Access  
Nova Scientia     Open Access  
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin     Hybrid Journal   (Followers: 4)
Nuclear Engineering and Design     Hybrid Journal   (Followers: 12)
Numerical Algorithms     Hybrid Journal   (Followers: 2)
Numerical Heat Transfer, Part A: Applications: An International Journal of Computation and Methodology     Hybrid Journal   (Followers: 5)
Numerical Heat Transfer, Part B: Fundamentals: An International Journal of Computation and Methodology     Hybrid Journal   (Followers: 7)
Ocean Science Journal     Hybrid Journal   (Followers: 3)
Oil and Gas Journal     Full-text available via subscription   (Followers: 11)
Online Journal for Global Engineering Education     Open Access  
Open Journal of Antennas and Propagation     Open Access  
Open Journal of Applied Sciences     Open Access  
Open Journal of Fluid Dynamics     Open Access   (Followers: 3)
Open Journal of Safety Science and Technology     Open Access   (Followers: 5)
Operations Research Letters     Hybrid Journal   (Followers: 5)
Optical Communications and Networking, IEEE/OSA Journal of     Hybrid Journal   (Followers: 4)
Optimization and Engineering     Hybrid Journal   (Followers: 3)
Opto-Electronics Review     Hybrid Journal   (Followers: 1)
OR Spectrum     Hybrid Journal   (Followers: 1)
Organic Electronics     Hybrid Journal   (Followers: 3)
Ozone Science & Engineering     Hybrid Journal   (Followers: 1)
Papers In Regional Science     Hybrid Journal   (Followers: 6)
Particle & Particle Systems Characterization     Hybrid Journal  
Particulate Science and Technology: An International Journal     Hybrid Journal   (Followers: 2)
Perspectives on Science     Hybrid Journal   (Followers: 4)
Pesquisa Operacional     Open Access  
Pest Management Science     Hybrid Journal   (Followers: 5)
Petroleum Science     Full-text available via subscription   (Followers: 2)
Phase Transitions: A Multinational Journal     Hybrid Journal  
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (Followers: 5)
Physica B: Condensed Matter     Hybrid Journal   (Followers: 5)

  First | 5 6 7 8 9 10 11 12 | Last

Journal Cover Reactive and Functional Polymers     [SJR: 0.834]   [H-I: 55]
   [6 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1381-5148
   Published by Elsevier Homepage  [2584 journals]
  • Preparation of Core-Shell Structural Surface Molecular Imprinting
           Microspheres and Recognition of L-Asparagine Based on [N1111]Asn Ionic
           Liquid as Template
    • Abstract: Publication date: Available online 22 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Ji Li , Xiaoling Hu , Ping Guan , Renyuan Song , Xiangrong Zhang , Yimei Tang , Chaoli Wang , Liwei Qian
      Core-shell structural surface imprinting microspheres were prepared by a simple and effective method. This method combined reversible addition-fragmentation chain transfer (RAFT) with distillation precipitation polymerization RAFT reagent-containing microspheres on the surface. Tetramethylammonium asparagine ([N1111]Asn) ionic liquid or L-Asn, 4-vinylpyridine (4-VP), ethylene glycol dimethacrylate (EGDMA), and RAFT reagent-containing microspheres on the surface were used as template, functional monomer, cross-linker, and chain transfer agent (CTA), respectively. Two kinds of imprinted polymer were obtained, namely, AsnIL-MIPs and Asn-MIPs. The morphology and structure of the polymers were characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. The binding and selective recognition properties of L-Asn and its analogs were investigated in aqueous solution. Compared with L-Asn as template molecule, AsnIL-MIPs showed faster binding speed and better selective recognition. The binding reached saturation after 1h, and the selective recognition factor (α) reached 5.28 and 4.26 for the template against L-Asp and L-Arg, respectively. AsnIL-MIPs showed an improved binding rate, binding affinity, and significantly increased recognition.
      Graphical abstract image

      PubDate: 2015-01-24T14:51:28Z
       
  • Synthesis and ion responsiveness of optically active polyacetylenes
           containing salicylidene Schiff-base moieties
    • Abstract: Publication date: Available online 22 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Chunyu Zhang , Yu Zhang , Hexin Zhang , Yanming Hu , Xuequan Zhang , Toshio Masuda
      Acetylenic monomers containing salicylidene Schiff-base groups (1a and 1b) as well as Schiff-base and hydroxy groups (1c) were synthesized and polymerized with [(nbd)RhCl]2/Et3N catalyst to afford the corresponding polymers 2a-c with high molecular weights (M n = 2.6–7.2 × 105) in high yields (75–97%). Polarimetric, circular dichroism (CD), and UV-vis spectroscopic analyses indicated that the polymers formed helical structures with a predominantly one-handed screw sense. The addition of metal ions to salicylidene Schiff-base-containing polymers 2a and 2b produced insoluble polymer/metal complexes through ionic cross-linking as a result of salicylaldimine-metal ion complexation. Polymers 2b and 2c underwent a helix-coil transition upon the addition of HSO4 -, whereas these polymers did not exhibit responsiveness to other anions, such as F-, Cl-, and Br-.


      PubDate: 2015-01-24T14:51:28Z
       
  • Allylimidazolium salt based antibacterial polymer coatings produced by
           thiol-ene photocuring
    • Abstract: Publication date: Available online 13 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Mirinae Kim , Chiman Song , Dong Keun Han , Kwang-Duk Ahn , Seung Sang Hwang , Dong June Ahn , Man-Ho Kim
      Photocurable formulations containing trifunctional thiol, trifunctional ene, and antibacterial allylimidazolium salts have been employed for transparent antibacterial coatings. The antibacterial component 1-allyl-3-dodecylimidazolium salt (ADIm) is prepared and chemically attached to polymer networks using a one-step thiol-ene photocuring reaction. Ultra-small (USANS) and small angle neutron scattering (SANS) measurements show that the photocured polymers are loosely networked three-dimensional structures with a mass fractal of approximately 2.7±0.2. The minimum inhibitory concentration (MIC) for the ADIm was determined to be 500 ug/ml and 15.63 ug/ml for E. coli (Gram-negative) and S. aureus (Gram positive) bacteria, respectively. Coating formulations containing 10 mol% of the antibacterial ADIm photocured on glass substrates showed strong antibacterial activity against environmental bacteria such as E. coli and/or S. aureus.


      PubDate: 2015-01-15T13:16:37Z
       
  • Imidazolium salts grafted on cotton fibres for long-term antimicrobial
           activity
    • Abstract: Publication date: Available online 8 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Boris Izmaylov , Diana Di Gioia , Galy Markova , Irene Aloisio , Martino Colonna , Valery Vasnev
      New antimicrobial (AM) coatings based on imidazolium salts have been prepared linking the imidazolium salts to the cotton fabric using siloxane oligomers as coupling agents. Three different imidazolium salts, linked to the siloxane oligomers connected to the cotton fabric either with ionic or covalent linkages, have been used. FTIR analysis shows that the imidazolium salts are linked to the cotton fabric. All the coatings prepared have high antimicrobial activity at both concentrations tested (3% and 10% wt) and against a Gram positive and a Gram negative bacterium. The AM activity is mainly retained after 4 cycles of washing.


      PubDate: 2015-01-10T12:50:37Z
       
  • Preparation and swelling behaviors of a high temperature resistant
           superabsorbent using tetraallylammonium chloride as crosslinking agent
    • Abstract: Publication date: Available online 2 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Xiaoyun Zhang , Xiangpeng Wang , Liang Li , Sisi Zhang , Ruonan Wu
      A new high temperature resistant superabsorbent was synthesized through solution polymerization of acrylamide (AM) and partially neutralized acrylic acid (AA), using tetraallylammonium chloride (TAAC) as crosslinker, ammonium persulfate (APS) as initiator. Parameters that influence water absorbency of the superabsorbent at 25°C and 200°C such as molar ratios of AM to AA, TAAC to AA, APS to AA and neutralization degree, were investigated. Swelling behaviors of superabsorbent prepared at the optimum conditions in different pH and saline solutions were studied. The swelling ratios of superabsorbent in distilled water and 1wt% NaCl solution at 250°C reach 287g/g and 69g/g, respectively.


      PubDate: 2015-01-06T12:39:00Z
       
  • Separation of butyric acid in fixed bed column with solvent impregnated
           resin containing ammonium ionic liquid
    • Abstract: Publication date: Available online 2 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Marek Blahušiak , Štefan Schlosser , Július Annus
      Batch equilibrium and fixed bed column extraction experiments for the extraction of butyric acid (BA) into solvent impregnated resin (SIR) have been done. Microporous Amberlite XAD-1180N was impregnated with an ammonium ionic liquid (IL) trialkylmethylammonium bis(2,4,4-trimethylpentyl)phosphinate. The BA extraction capacity isotherm has not a Langmuir type shape and no finite capacity was observed. The loading of the impregnated IL with the extracted BA at 37 °C is in agreement with the loading from L/L extraction equilibrium of BA at 25 °C. Capacity of freshly prepared SIR particles is superior to classical porous ion-exchangers. Both the temperature and the superficial velocity in column influence the shape of the breakthrough-curve in fixed bed extraction of BA using SIR. Sharpening of the breakthrough curve was observed with the increasing temperature and decreasing superficial velocity. Stripping with water is not efficient for the regeneration of the loaded column after extraction because of low concentration of the product acid in the obtained effluent. Higher BA concentration was achieved by stripping with 0.15 kmol.m-3 and 0.075 kmol.m-3 NaOH solutions. The combination of initial water stripping coupled with consecutive stripping by alkali can be beneficial for decreasing the consumption of chemicals and further processing of the product. After two extraction/stripping cycles, a stable capacity was achieved and sustained for 14 cycles, showing the possibility of long-term application of the prepared SIR in real technology.


      PubDate: 2015-01-06T12:39:00Z
       
  • Urease-carrying electrospun polyacrylonitrile mat for urea hydrolysis
    • Abstract: Publication date: Available online 5 January 2015
      Source:Reactive and Functional Polymers
      Author(s): Aref Daneshfar , Takeshi Matsuura , Daryoush Emadzadeh , Zahra Pahlevani , Ahmad Fauzi Ismail
      Electrospinning was used to fabricate beadless microfibrous polyacrylonitrile (ePAN) mats with an average fiber diameter of 1448 ± 380 nm from a 10 wt % PAN in dimethylformamide (DMF) dope solution at applied voltage of 18 kV and 20 cm fiber collection distance. Urease (EC 3.5.1.5) was then covalently immobilized on dispersed microfibrous ePAN mats following the chemical treatment of fibers with ethylenediamine (EDA) and glutaraldehyde (GA). The optimal concentration of GA for immobilization was 5 %. The amount of loaded urease reached 157 μg/mg mat, exhibiting 54 % of the free urease activity. The surface chemistry of as–spun and chemically treated fibers was examined with Fourier transform infrared (FTIR) spectroscopy. Field emission scanning electron microscopy (FESEM) was used to study the morphology and diameter of the pristine, chemically treated, and urease-immobilized microfibrous mats. Immobilized urease showed increased temperature for maximum activity (from 37 to 50 °C for free and immobilized urease, respectively) and improved storage stability (20 days). The immobilized urease was also less sensitive to the changes in pH, especially in acid conditions. In addition, nearly 70 % of initial activity of the immobilized urease was retained after 15 cycles of reuse, which proved the applicability of the electrospun fibers as successful enzyme carriers.


      PubDate: 2015-01-06T12:39:00Z
       
  • Study of synthesis parameters and active layer morphology of interfacially
           polymerized polyamide–polysulfone membranes
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Sanne Hermans , Roy Bernstein , Alexander Volodin , Ivo F.J. Vankelecom
      Thin film composite (TFC) polyamide membranes were prepared on a polysulfone support membrane and the effect of various synthesis conditions on the active layer morphology, the physicochemical properties and the membrane performance was investigated. The support membrane porosity factor had a significant effect on the TFC membrane performance. A polyamide top layer was formed within 15s of reaction. Prolonging the reaction time, although resulting in a thicker active layer, only had a minor influence on the membrane performance. This highlights the importance of the incipient layer of the polyamide structure on its performance. The addition of both a surfactant and a base to the amine solution resulted in a change of the active layer morphology and an improved performance. The effect of additives was attributed to changes in the polymerization mechanism. In addition, it was demonstrated that curing at 50°C resulted in an improved membrane performance, due to more cross-linking of the active layer. Curing at higher temperatures deteriorated the structure of the support membrane. This research shows that the TFC membrane performance is well correlated with the changes in the active layer morphology, measured using SEM, AFM and TEM; whereas only minor changes in the physicochemical characteristics of the membranes were detected by zeta potential and ATR-FTIR spectroscopy when the same synthesis parameters were varied.


      PubDate: 2014-12-25T11:32:51Z
       
  • Targeted gas separations through polymer membrane functionalization
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Melinda L. Jue , Ryan P. Lively
      Gas separation membranes have been studied for several decades and are starting to find commercial acceptance. This review will focus on polymer functionalization to improve gas separation performance, namely, permeability, permselectivity, or both. The review will cover both “diffusivity controlled” and “solubility controlled” functionalization strategies; each strategy refers to the different mode of gas transport through the membrane. Diffusivity controlled functionalization strategies mainly involve control over free volume elements in amorphous polymers via promotion or inhibition of chain packing through functional groups. As such, the effects of this functionalization are typically confined to the well-known selectivity/permeability tradeoff. Solubility controlled modification strategies utilize functional groups that have strong chemical interactions with some of the penetrant molecules and offers an enhanced solution-diffusion or a non-solution-diffusion permeation pathway. This functionalization can potentially exceed the Robeson upper bound, but is often challenged by impurities and deactivation of the chemical functionality.


      PubDate: 2014-12-25T11:32:51Z
       
  • Obituary: Takakazu Yamamoto, 1944–2014
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86




      PubDate: 2014-12-25T11:32:51Z
       
  • Adsorption and recognition of protein molecular imprinted calcium
           alginate/polyacrylamide hydrogel film with good regeneration performance
           and high toughness
    • Abstract: Publication date: Available online 22 December 2014
      Source:Reactive and Functional Polymers
      Author(s): Kongyin Zhao , Tian Chen , Beibei Lin , Wenkui Cui , Bohong Kan , Ning Yang , Xiangyu Zhou , Xinxin Zhang , Junfu Wei
      Protein imprinted calcium alginate/polyacrylamide hydrogel film (CA/PAM MIP) with high toughness was prepared using bovine serum albumin (BSA) as template molecule, sodium alginate and acrylamide as functional monomers, N, N′-methylenebisacrylamide (MBAA) as the covalent cross-linker and CaCl2 as the ionic cross-linker via UV radiation-reduced polymerization. Factors affecting the adsorption capacity and imprinting efficiency of the BSA-imprinted CA/PAM hydrogel films were investigated, such as ratio of polyacrylamide/sodium alginate, film thickness, MBAA concentration and CaCl2 concentration. Results showed that the CA/PAM MIP exhibited an obvious improvement in terms of adsorption capacity for BSA compared with non-imprinted polymer (NIP). The adsorption capacity of MIP for BSA reached 22.49 mg/g, which was 2.7 times higher than NIP. The regeneration property of the BSA-imprinted CA/PAM hydrogel was distinctly improved and the imprinting efficiency of CA/PAM MIP maintained 77.95% of the initial value after five repetitions. Single and binary proteins rebinding indicated that the CA/PAM MIP exhibited good recognition performance. Cell culture experiments showed CA/PAM MIP was more suitable for cell culture than CA/PAM NIP. The residual sodium dodecyl sulfate (SDS) in the elution process leaded to the death of mouse fibroblast cells (L929) after 3 days. A moderate elution solution without residue eluent should be used to prepare MIP for cell culture.


      PubDate: 2014-12-25T11:32:51Z
       
  • Influence of molecular weight of polydimethylsiloxane precursors and
           crosslinking content on degree of ethanol swelling of crosslinked networks
           
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Wanqiu Zhang , Xing Su , Baoli Shi , Lili Wang , Qingwen Wang , Shujun Li
      Using PDMS (polydimethylsiloxane) as a basic polymeric matrix to the preparation of ethanol-permselective pervaporation membranes is a vibrant field of research. In this paper, a detailed study of the effects of the molecular weight of PDMS precursors and the content of the TEOS (tetraethyl orthosilicate) crosslinker on the degree of swelling in ethanol and ethanol contact angle is reported. Five PDMS precursors with molecular weights of 26.6K, 35.5K, 50.2K, 71.7K, and 110.4K, and five crosslinking contents (1wt%, 2wt%, 5wt%, 10wt%, and 15wt%) were chosen to prepare twenty-five PDMS networks. Considering only the maximum tensile strength of the networks, the optimum molecular weight of the precursor was found to be 35.5K and the optimum crosslinker content was 5wt%. The average Young’s modulus of the PDMS network prepared under these conditions reached 0.63MPa after using toluene to extract the network. Some uncrosslinked precursors always occur in the networks, and have some influence on the molecular weight of the precursors and the crosslinker content that is used. It was found that the content of the uncrosslinked precursors has direct effect on the contact angle of ethanol sessile drops at the surface of the extracted PDMS networks, and higher extraction corresponded to a smaller ethanol contact angle. A combined parameter (S), defined as the quotient of the extraction amount (AE ) and the tensile elastic modulus (EY ), gives a good linear relationship with the increase in weight of networks swelled in ethanol. This means that the degree of equilibrium swelling of the networks is simultaneously strongly influenced by the tensile modulus and the content of the uncrosslinked precursors.


      PubDate: 2014-12-25T11:32:51Z
       
  • Functionalization of polymeric materials as a high performance membrane
           for direct methanol fuel cell: A review
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): N. Awang , A.F. Ismail , J. Jaafar , T. Matsuura , H. Junoh , M.H.D. Othman , M.A. Rahman
      A coherent review on the advanced proton exchange membranes (PEMs) for direct methanol fuel cell (DMFC) application and the future direction in the development of a high performance polymeric membrane for DMFC were discussed in this paper. PEMs have a profound influence on performance of DMFC. The PEMs are categorized into five groups which are partially fluorinated, perfluorinated ionomers, acid–base complexes, non-fluorinated ionomers, hydro carbon and aromatic polymers. Many researchers have investigated the functionalization methods on the PEMs to solve methanol crossover problem while obtaining low electronic conductivity, high proton conductivity, low electro osmotic drag coefficient, high mechanical properties and good chemical and thermal stability. Including in this review, fabrication of PEM using electrospinning process coupled with the promising functionalized polymeric materials which were known to be the most important initiatives at present in order to further expand the full potential of DMFC performance.


      PubDate: 2014-12-25T11:32:51Z
       
  • Ion-fuelled L-Phenylalanine controlled pumping by hybrid membrane
           materials
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Pascal Blondeau , Mihail Barboiu , Eddy Petit
      We report organic–inorganic membrane materials for controlled translocation of ion-pairs along directional conduction pathways. The supramolecular/sol–gel combined procedure has been realised in two steps. First, the self-organization properties of 3-(ureidoarene)propyltriethoxysilane compound, 1 in aprotic solvents were determined, revealing the formation of supramolecular oligomers, in the self-assembly step. They led in a second sol–gel transcription step to hybrid membrane materials. Then, the transport of organic molecules of variable charge, like L-Phenylalanine can be directionally tuned, via ion-fuelled membrane polarization phenomena. Using this strategy, the transport of the cationic, zwitterionic and anionic forms of the L-Phenylalanine can be controlled and directionally oriented from the feed to strip phase and vice versa.


      PubDate: 2014-12-25T11:32:51Z
       
  • Study of glassy polymers fractional accessible volume (FAV) by extended
           method of hydrostatic weighing: Effect of porous structure on liquid
           transport
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Alexey Yushkin , Alexey Grekhov , Samira Matson , Maxim Bermeshev , Valery Khotimsky , Evgeny Finkelstein , Peter M. Budd , Vladimir Volkov , Thijs J.H. Vlugt , Alexey Volkov
      In this study, 11 different hydrophobic materials made of high permeability glassy polymers such as PTMSP, PBTMST, PTMST, PTMGP, PMP, PIM-1, PVTMS, as well as polymeric blends based on PTMSP/PVTMS with varied fractional free volume, were studied by the extended method of hydrostatic weighing. Results clearly indicate the presence of interconnected pre-existing free volume elements (microcavities or micropores), which are accessible for the liquid molecules without polymer swelling. Depending on the polymer, the contribution of pre-existing microcavities to the free volume of polymer varies from 35% for PIM-1 to 85% for PTMSP/PVTMS (90/10). Using the proposed method, it was possible to estimate total fractional accessible volume FAV t: PTMSP (30%)>PTMSP/PVTMS (90/10) (27%)>PTMSP/PVTMS (80/20) (25%)>PBTMST (24%)>PTMST (23%)>PTMGP (22%)>PTMSP/PVTMS (70/30) (21%)>PIM-1 (17%)>PMP (16%)>PTMSP/PVTMS (40/60) (11%)>PVTMS (4%). The applicability of the extended method of hydrostatic weighing for evaluation of the porous structure of the polymeric materials was confirmed by good agreement with the literature data on fractional free volume FFV estimated by PALS. FAV can be considered as a uniform parameter to describe the solvent transport regardless of the difference in the nature of high permeability glassy polymers. It was found that there is a threshold value of FAV t, estimated as 12%, which is required for establishment of liquid permeability. FAV t values obtained for PVTMS (4%) and PTMSP/PVTMS (40/60) (11%) were not high enough to provide the formation of liquid percolation clusters, and, hence, liquid transport across the membrane at 20bar. Investigation of water–ethanol transport through PTMSP, PTMGP, PMP and PIM-1 showed that all polymers had two regions: (i) at lower concentration of ethanol, hydrophobic glassy polymers showed absence or hardly detectable liquid transport, (ii) the increase of ethanol concentration led to the establishment and further increase of liquid transport through the dense membranes. PTMSP, PTMGP, PMP and PIM-1 kept their barrier properties till the threshold value of FAV was equal to 26%, 17%, 15% and 12%, respectively. Such behavior was explained in terms of boundary conditions for formation of a percolation cluster within a specific glassy polymer with respect to its properties and chemical nature. Once such clusters were formed in the bulk material, no further noticeable increase in FAV t was required to enhance the liquid transport through the membrane. The different behavior of PIM-1 was attributed to the presence of a noticeable fraction of isolated holes.
      Graphical abstract image Highlights

      PubDate: 2014-12-25T11:32:51Z
       
  • Cross-linked PAN-based thin-film composite membranes for non-aqueous
           nanofiltration
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Liliana Pérez-Manríquez , Jamaliah Aburabi’e , Pradeep Neelakanda , Klaus-Viktor Peinemann
      A new approach on the development of cross-linked PAN based thin film composite (TFC) membranes for non-aqueous application is presented in this work. Polypropylene backed neat PAN membranes fabricated by phase inversion process were cross-linked with hydrazine to get excellent solvent stability toward dimethylformamide (DMF). By interfacial polymerization a selective polyamide active layer was coated over the cross-linked PAN using N,N′-diamino piperazine (DAP) and trimesoyl chloride (TMC) as monomers. Permeation and molecular weight cut off (MWCO) experiments using various dyes were done to evaluate the performance of the membranes. Membranes developed by such method show excellent solvent stability toward DMF with a permeance of 1.7L/m2 hbar and a molecular weight cut-off of less than 600Da.


      PubDate: 2014-12-25T11:32:51Z
       
  • Thin-film composite membranes for organophilic nanofiltration based on
           photo-cross-linkable polyimide
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Sven Behnke , Mathias Ulbricht
      This work demonstrates that it is possible to prepare new, competitive thin-film composite (TFC) membranes with a polyolefin ultrafiltration membrane as support and with a non-porous photo-cross-linked polyimide as separation layer for organic solvent nanofiltration. The commercial polyimide Lenzing P84® was modified by a polymer-analogous reaction to introduce side groups with carbon–carbon double bonds to increase its photo-reactivity with respect to cross-linking. Polymer characterization revealed that this was successfully achieved at acceptable level of main chain scission. The higher reactivity of the photo-cross-linkable polyimide had been confirmed by comparison with the original polymer; i.e., shorter gelation times upon UV irradiation, higher suppression of swelling by solvents and complete stability in strong solvents for not cross-linked polyimide such as dimethylformamide (DMF) had been obtained. For films from unmodified and modified polyimide, the degree of swelling in various solvents could be adjusted by UV irradiation time. Photo-cross-linking of the original polyimide did not lead to stability in DMF. TFC membranes had been prepared by polymer solution casting on a polyethylene ultrafiltration membrane, UV irradiation of the liquid film and subsequent solvent evaporation. Polyimide barrier film thicknesses between 10 and 1μm were obtained by variation of cast film thickness. Performance in organic solvent nanofiltration was analyzed by using hexane, toluene, isopropanol and DMF as well as two dyes with molar masses of ∼300 and ∼1000g/mol. Permeances of TFC membranes from unmodified polyimide were low (<0.1L/hm2 bar) while rejections of up to 100% for the dye with ∼1000g/mol could be achieved. TFC membranes from modified and photo-cross-linked polyimide had adjustable separation performance in DMF with a trade-off between permeance and selectivity, in the same range (e.g.: 0.3L/hm2 bar and 97% rejection for the dye with ∼1000g/mol) as a commercial conventional polyimide membrane tested in parallel. The established membrane preparation method is promising because by tuning the degree of cross-linking of the polymeric barrier layer, the membrane separation performance could be tailored within the same manufacturing process.


      PubDate: 2014-12-25T11:32:51Z
       
  • Thin-film composite crosslinked polythiosemicarbazide membranes for
           organic solvent nanofiltration (OSN)
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Jamaliah Aburabie , Pradeep Neelakanda , Madhavan Karunakaran , Klaus-Viktor Peinemann
      In this work we report a new class of solvent stable thin-film composite (TFC) membrane fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate that exhibits superior stability compared with other solvent stable polymeric membranes reported up to now. Integrally skinned asymmetric PTSC membranes were prepared by the phase inversion process and crosslinked with an aromatic bifunctional crosslinker to improve the solvent stability. TFC membranes were obtained via interfacial polymerization using trimesoyl chloride (TMC) and diaminopiperazine (DAP) monomers. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement. The membranes exhibited high fluxes toward solvents like tetrahydrofuran (THF), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) ranging around 20L/m2 h at 5bar with a molecular weight cut off (MWCO) of around 1000g/mol. The PTSC-based thin-film composite membranes are very stable toward polar aprotic solvents and they have potential applications in the petrochemical and pharmaceutical industry.


      PubDate: 2014-12-25T11:32:51Z
       
  • Molecularly imprinted organic solvent nanofiltration membranes –
           Revealing molecular recognition and solute rejection behaviour
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): György Székely , Irina B. Valtcheva , Jeong F. Kim , Andrew G. Livingston
      A new class of organic solvent nanofiltration (OSN) membranes featuring molecular recognition sites has been fabricated by a phase inversion molecular imprinting technique. Polybenzimidazole (PBI) was employed as a functional polymer for molecular imprinting for the first time. Apart from acting as a functional polymer, PBI exhibits excellent chemical and solvent stability and can be used as a nanofiltration membrane, acting both as shape-specific adsorbent and size-exclusion membrane. The molecularly imprinted organic solvent nanofiltration (MI-OSN) membranes fabricated in this study showed both nanofiltration membrane performance, and excellent molecular recognition ability. The model system comprised roxithromycin pharmaceutical, 2-aminopyrimidine building block and N,N-dimethylaminopyridine catalyst, which are retained, adsorbed and permeated through the MI-OSN membrane, respectively. The effect of both dope solution concentration and applied pressure on the molecular recognition behaviour of MI-OSN membranes has been investigated by employing Sips and Freundlich adsorption isotherms, as well as examining the physical morphology of the membranes. The rate of adsorption was investigated, revealing that the adsorption follows second-order kinetics and is not limited by diffusion. The imprinted membrane exhibited fourfold higher flux whilst maintaining the same rejection performance in comparison to the control membrane. It is shown that increasing the transmembrane pressure across the MI-OSN membrane irreversibly suppresses the molecular recognition whilst maintaining the rejection and flux performance.
      Graphical abstract image Highlights

      PubDate: 2014-12-25T11:32:51Z
       
  • Composite membranes from polyacrylonitrile with
           poly(N,N-dimethylaminoethyl methacrylate)-grafted silica nanoparticles as
           additives
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Suo-Hong Zhi , Ran Deng , Jun Xu , Ling-Shu Wan , Zhi-Kang Xu
      Polyacrylonitrile (PAN)-based composite membranes were prepared by immersion precipitation method by using poly(N,N-dimethylaminoethyl methacrylate)-grafted silica (PDMAEMA@SiO2) nanoparticles as hydrophilic additives. The molecular weight of PDMAEMA were controlled by the surface initiated atom transfer radical polymerization of N,N-dimethylaminoethyl methacrylate on SiO2 nanoparticles. The synthesized nanoparticles have a typical core–shell structure as characterized in detail by FT-IR, TEM, DLS and GPC. The prepared PAN-based composite membranes have higher porosity and water permeation flux than those of the pure PAN membranes. They also show high rejection (⩾90%) to bovine serum albumin and high flux recovery ratio (⩾90%) to water permeation. These improved performances are attributed to the good hydrophilicity of PDMAEMA@SiO2 nanoparticles. The results suggest that PDMAEMA@SiO2 nanoparticles are suitable for the property optimization of PAN-based composite membranes.


      PubDate: 2014-12-25T11:32:51Z
       
  • Positively charged loose nanofiltration membrane grafted by diallyl
           dimethyl ammonium chloride (DADMAC) via UV for salt and dye removal
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Fu Liu , Bi-rong Ma , Dong Zhou , Li-Jing Zhu , Yin-Yi Fu , Li-xin Xue
      A novel positively charged loose nanofiltration (NF) membrane was fabricated feasibly by UV-induced photografting polymerization of diallyl dimethyl ammonium chloride (DADMAC) on Polysulfone ultrafiltration membrane. A possible reaction mechanism was proposed that a linear chain structure and/or pyrrolelike five-membered nitrogen heterocycles structure on the side chain were grafted to form the active barrier layer. NF membrane demonstrated a looser average pore size of 8.6nm and positive charges surface. Owing to the nanoscale ultrathin nanoscale barrier layer and the combination of Donnan exclusion and steric hindrance, NF membrane exhibited good hydrophilicity, a high pure flux of 60L/m2 h (0.5MPa), a good salt rejection to Mg2+ (90.8%), Al3+ (94.0%), Ca2+ (91.5%), and a high dye rejection to methylene blue (99.4%) and congo red (100.0%) respectively. The salts rejection of NF membrane to different salts followed the order of AlCl3 >CaCl2 >MgCl2 >NaCl>LiCl>MgSO4 >Na2SO4. NF membrane showed certain fouling resistance to seawater and BSA solution. The grafting polymerization kinetics were comprehensively investigated including irradiation time, monomer concentration and irradiation intensity. X-ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurement were employed to investigate membrane chemistry, morphologies, and hydrophilicity.


      PubDate: 2014-12-25T11:32:51Z
       
  • Surface modification of composite ion exchange membranes by polyaniline
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): H. Farrokhzad , M.R. Moghbeli , T. Van Gerven , B. Van der Bruggen
      The aim of this work is to develop new selective cation exchange membranes (CEMs) from bivalent to monovalent selectivity by surface functional groups. So, a novel hybrid cation exchange membrane was prepared by polymerization of polyaniline on a composite membrane, made of polyvinylidene fluoride (PVDF) and sulfonated PVDF (S-PVDF). Polyaniline was doped with different doping agents and their effect on total salt extraction and selectivity of bivalent to monovalent cations was evaluated. The chemical and morphological properties of hybrid membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ion exchange capacity (IEC), transport number, ion conductivity and water uptake decreased after surface polymerization. Composite membrane has a good selectivity (∼2) for bivalent and excellent removal of both cations. The hybrid membrane, doped with pTSA has a very high selectivity for monovalent ions (∼7.1) and a high removal of monovalent ions.


      PubDate: 2014-12-25T11:32:51Z
       
  • Thin film composite nanofiltration membranes fabricated from polymeric
           amine polyethylenimine imbedded with monomeric amine piperazine for
           enhanced salt separations
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Dihua Wu , Sanchuan Yu , Darren Lawless , Xianshe Feng
      Thin film composite (TFC) nanofiltration membranes were fabricated by interfacial polymerization using polymeric amine polyethylenimine (PEI) and monomeric amine piperazine (PIP) as the amine reactant. Membranes with a single-ply polyamide layer were produced by reacting trimesoyl chloride (TMC) with mixed amines of PEI and PIP, and incorporation of a small amount of PIP in PEI was found to increase the permeation flux effectively while still maintaining a good solute rejection. For instance, adding 10wt% PIP in the amine reactant solution resulted in a 6-fold increase in permeation flux, while a 91.6% MgCl2 rejection was maintained. In addition, 2-ply polyamide membranes were also prepared by two cycles of PEI–TMC and PIP–TMC interfacial reactions separately, and they showed a higher rejection than the single-ply polyamide membrane. At a low PIP/PEI concentration ratio, the single-ply polyamide membranes formed with mixed amines of PIP and PEI tended to be more permeable than the 2-ply polyamide membranes. However, it was demonstrated that by properly controlling the PIP/PEI concentration ratio, the 2-ply polyamide membranes with both a higher permeation flux and salt rejection than conventional single-ply polyamide membranes could be produced. The resulting membranes were characterized for chemical composition, surface hydrophilicity, surface charge and morphology of the polyamide skin layer.


      PubDate: 2014-12-25T11:32:51Z
       
  • Poly(vinylidene fluoride) (PVDF) membranes for fluid separation
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Jing Ji , Fu Liu , N. Awanis Hashim , M.R. Moghareh Abed , Kang Li
      The importance of poly(vinylidene fluoride) (PVDF) as a membrane material has long been recognised in many membrane processes. Compared to other types of polymeric membranes, the PVDF membranes have received great attention because of its outstanding properties including high hydrophobicity, thermal stability, chemical resistance and excellent mechanical strength. This article provides an overview of recent development in PVDF membrane processes, focussing on the commercial PVDF membrane products for water and wastewater treatment and possible applications of PVDF membranes in areas such as membrane based gas absorption and membrane distillation where no substantial commercial PVDF membrane processes are available so far.


      PubDate: 2014-12-25T11:32:51Z
       
  • Enhanced hollow fiber membrane performance via semi-dynamic layer-by-layer
           polyelectrolyte inner surface deposition for nanofiltration and forward
           osmosis applications
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Chang Liu , Lei Shi , Rong Wang
      The layer-by-layer (LBL) polyelectrolyte deposited membranes have drawn increasing attention in various applications due to the ease of selective layer formation and their stability and versatility. In this study, the LBL deposition was performed at the inner surface of the polyethersulfone (PES) hollow fiber substrate to form composite nanofiltration (NF) membrane. The semi-dynamic deposition procedure was adopted with the aid of syringes. The newly developed inner deposited (id-LBL) membranes were then tested in NF and forward osmosis (FO) applications and the performance were compared with outer surface deposition as well as some literature data. The id-LBL membranes could not only withstand higher operating pressure but also possess superior hardness rejection especially in high concentration mixed salt solutions (more than 95% rejection to Mg2+ and Ca2+ in a 5000ppm total dissolved salt (TDS) mixture under 4.8bar). As for the FO process, with only two layer deposition, the id-LBL membranes also demonstrated significant performance improvement with increased water flux (up to 70L/m2 h using 0.5M MgCl2 as draw solution in active layer facing draw solution configuration) and reduced salt leakage (around 0.5g/m2 h using 1M MgCl2 draw solution in active layer facing feed water configuration). This study suggests that for hollow fiber substrate, the inner surface is more suitable for the formation of the selective layer via LBL deposition than the outer surface.


      PubDate: 2014-12-25T11:32:51Z
       
  • Functionalization of POSS nanoparticles and fabrication of block copolymer
           nanocomposite membranes for CO2 separation
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Md. Mushfequr Rahman , Volkan Filiz , Muntazim Munir Khan , Bahadir N. Gacal , Volker Abetz
      Synthesis of methoxy poly(ethylene glycol) (PEG) functionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticles via epoxy ring opening reaction in three different solvents are outlined in this manuscript. The nanoparticles are used as filler for commercial poly(ether-block-amide) multiblock copolymer PEBAX® MH 1657. The influence of two novel structural features of the synthesized nanofillers on the gas separation performance of nanocomposite membranes are studied on the examples of CO2/N2 and CO2/H2 gas pairs. These are – (i) presence of a dimethylsilyl group as spacer between the cage structure of POSS and the PEG ligand and (ii) formation of a tetrahydrofuran (THF) complex. While ideal selectivity characteristics for the matrix polymer are not significantly affected by the presence of fillers, the single gas permeability (determined by time-lag method) is remarkably increased in both cases.


      PubDate: 2014-12-25T11:32:51Z
       
  • Water vapor and CO2 transport through amine-containing facilitated
           transport membranes
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Zi Tong , Varun K. Vakharia , Michael Gasda , W.S. Winston Ho
      Amine-containing CO2 facilitated transport membranes have great potential to be applied for hydrogen purification from synthesis gas. In some applications, the humidity of the retentate stream is required as well as the purity of hydrogen. The membranes are highly hydrophilic, and they exhibit not only high CO2 permeance but also high water vapor permeance. In this work, the transport of water vapor and CO2 through the membranes composed of an amine-containing selective layer and a microporous polysulfone substrate was investigated. From the experiments conducted, water vapor permeance appeared to be independent of the selective layer thickness, indicating that the substrate is the controlling factor of the mass transfer resistance to water vapor transport. Moreover, water vapor permeance appeared to reduce linearly with increasing the number of the substrate layers. But, CO2 permeance and CO2/H2 selectivity did not change significantly as the number of the substrate layers increased. These results indicated that the CO2 separation performance is governed by the selective layer as expected. In addition, the membranes synthesized from Lupamin® containing 34% polyvinylamine and 66% salt (sodium formate) demonstrated better CO2 separation performance than those from pure polyvinylamine, presumably due to better water retention capability of the salt than polyvinylamine.


      PubDate: 2014-12-25T11:32:51Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86




      PubDate: 2014-12-25T11:32:51Z
       
  • Editorial “Polymers for membrane applications”
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Alexander Bismarck , Kang Li , Andrew Livingston



      PubDate: 2014-12-25T11:32:51Z
       
  • Synthesis of a novel zwitterionic bisphosphonate cyclopolymer containing
           residues of alendronic acid
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Shaikh A. Ali , Hasan A. Al-Muallem , Othman Charles S.O. Al-Hamouz , Mohamad K. Estaitie
      The reaction of 4-(diallylammonio)butanoate, H3PO3 and PCl3 in CH3SO3H created water-insoluble 4-diallylamino-1-hydroxybutylidene-1,1-bisphosphonic acid I, a novel monomer that contained residues of the osteoporosis drug alendronic acid. Monomer (±) I, a zwitterionic tetraprotic acid, in the presence of 2 equivs. NaOH(aq) and the initiator ammonium persulfate, underwent cyclopolymerization to yield water-soluble poly(zwitterion–dianion) (± =) II. Under the influence of pH, II was equilibrated to water-soluble poly(zwitterion–trianion) (± ≡) III, polytetraanion (= =) IV, poly(zwitterion–anion) (± −) V, cationic polyelectrolyte (+) VI and water-insoluble polyzwitterion (±) VII. The solution properties of backbone charges were investigated, and protonation constants of several centers in IV were determined. Polymers that contained residues of alendronic acid should have applications in various fields, including the field of medicine.


      PubDate: 2014-12-20T11:29:02Z
       
  • Selective recovery of a pyridine derivative from an aqueous waste stream
           
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): J. Bokhove , T.J. Visser , B. Schuur , A.B. de Haan
      Solvent impregnated resins (SIRs) were evaluated for the recovery of pyridine derivatives from an aqueous waste-stream containing also acetic acid and succinonitrile. For this purpose, a new solvent was developed, synthesized and impregnated in Amberlite XAD4. Sorption studies were used to determine the capacity, selectivity and the mass-transfer rate. A high capacity of 21g 4-cyanopyridine (CP) per kg SIR was found, with very high selectivity toward CP over the other solutes of at least 570. A modified Langmuir equation could describe the equilibrium sorption isotherm. Both the linear driving force model and a Fickian diffusion model were evaluated. The Fick-model described both regeneration and loading best. The CP-diffusivity through the solvent phase was estimated at 6.53·10−13 ±2.5% m2 s−1. The model was validated using fixed-bed column experiments. The R 2 values for this model ranged between 0.94 at a flow rate of 5mL/min and 0.99 at a flow rate of 1mL/min during the loading cycle. Due to mass-transfer limitations the breakthrough profiles were broad and breakthrough occurred after 5 or 23 bed volumes, for flow rates of 5 and 1mL/min, respectively. Both acetic acid and succinonitrile broke through immediately due to the very high CP-selectivity of the SIR.


      PubDate: 2014-12-20T11:29:02Z
       
  • Tuning the morphology of electroactive polythiophene nano-structures
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Bartlomiej Kolodziejczyk , Orawan Winther-Jensen , Robert Kerr , Paul Firbas , Bjorn Winther-Jensen
      The self-assembly of thiophene monomers and the subsequent oxidative polymerization of them has been studied using the vapour phase polymerization (VPP) platform. A variety of nano-structures were obtained by varying the polymerization conditions with regard to temperature, time, addition of a secondary oxidant and crystal formation in the oxidant layer. The electrochemical and physical characterizations of these nano-structured polythiophene materials were performed using cyclic voltammetry, electron microscopy, UV–vis spectroscopy, conductivity, contact angle and BET surface area measurements. The presence of nano-structures indeed enhances the redox capacity and increases the active surface area compared to the analogue film without nanostructures. The hydrophobicity of the polymeric film is also tuneable from different nano-structures forming on top of the film.


      PubDate: 2014-12-20T11:29:02Z
       
  • The non-trivial role of native xylans on the preparation of TEMPO-oxidized
           cellulose nanofibrils
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): Qijun Meng , Hailong Li , Shiyu Fu , Lucian A. Lucia
      Cellulose nanofibrils have become increasingly prized as a raw material toward the preparation of composites due to their specific surface character and biocompatibility. TEMPO-mediated oxidation with post-mechanical treatment has been proposed as a promising method for the preparation of cellulose nanofibrils from cellulosic raw materials. In the current study it was found that the native hemicellulosic components in the raw material played a pivotal chemical role on the kinetics of generation of TEMPO-oxidized cellulose nanofibrils (TOCNs), as well as on thermal stability, and transmittance. The removal of xylans from the original feedstock facilitated not only an increase in both the carboxylate content and water retention value of the TEMPO-oxidized fibers, but also improved the transmittance of subsequently obtained TOCNs suspensions. It was also determined that the presence of xylans in the cellulosic feedstock hindered chemical accessibility through a barrier mechanism in which the TEMPO-mediated oxidation reaction rate was reduced.


      PubDate: 2014-12-20T11:29:02Z
       
  • Influence of mechanical treatments on the properties of cellulose
           nanofibers isolated from microcrystalline cellulose
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): Davide Bandera , Janak Sapkota , Sébastien Josset , Christoph Weder , Philippe Tingaut , Xin Gao , E. Johan Foster , Tanja Zimmermann
      The possibility of preparing cellulose whiskers-like materials by mechanical treatment of commercially available microcrystalline cellulose (MCC) was explored. High shear homogenization, grinding with a supermass colloider, and hammer-milling were the processes selected to disintegrate the MCC, which yielded F-MCC, G-MCC and H-MCC, respectively. Processing aqueous dispersions with high solid content allowed for the production of cellulose particles with greatly reduced dimensions. Morphological characterization revealed that homogenization and grinding reduced the particle size more effectively than hammer-milling, although the disintegration was incomplete in all cases. The reinforcing potential of the materials was evaluated against commercially available whiskers by using the various particles as fillers to mechanically reinforce hydroxypropylcellulose. Nanocomposite films containing 5, 10, or 20wt.% of the filler were prepared and the mechanical properties were characterized. The results show that H-MCCs are just slightly better than the original MCC, whereas F-MCC and G-MCC performed similar to whiskers at 10wt.% loading, despite the presence of a fraction of micrometer-sized particles. It is therefore reasonable to envision the use of the more easily produced F-MCC and G-MCC as replacement of cellulose whiskers in some applications.


      PubDate: 2014-12-20T11:29:02Z
       
  • TEMPO-oxidized cellulose nanofibrils prepared from various plant
           holocelluloses
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): Ryota Kuramae , Tsuguyuki Saito , Akira Isogai
      Plant holocelluloses were prepared from softwood, gymnosperm, hardwood, and herbaceous species, and subjected to TEMPO-mediated oxidation using the TEMPO/NaBr/NaOCl and TEMPO/NaOCl/NaO2Cl systems in water at pH 10 and 6.8, respectively. Weight recovery ratios of the water-insoluble TEMPO-oxidized holocellulose (TOH) fractions and their carboxylate contents, sugar compositions, and X-ray diffraction patterns were measured. When the oxidation at pH 10 was used, the carboxylate content of the TOHs increased up to 1.4–1.7mmolg− 1. The oxidation at pH 6.8 resulted in higher weight recovery ratios of TOHs and their lower carboxylate contents (0.8–1.2mmolg− 1) than those prepared by the oxidation at pH 10. Hemicelluloses in plant holocelluloses are preferentially degraded to water-soluble fractions and removed from TOHs in the oxidation at pH 10. In contrast, the TEMPO-mediated oxidation at pH 6.8 provides hemicellulose-rich TOHs in high weight recovery ratios, although their nanofibrillation yields were low. All TEMPO-oxidized holocellulose nanofibrils (TOHNs) obtained by mechanical disintegration treatment of TOHs in water had the same average widths of ∼3nm, when measured by atomic force microscopy in water, which were consistent with those of TOHs determined from X-ray diffraction patterns. The number-average lengths of TOHNs were 500–600nm.
      Graphical abstract image Highlights

      PubDate: 2014-12-20T11:29:02Z
       
  • Surface maleylation and naphthaloylation of chitin nanofibers for property
           enhancement
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): S. Ifuku , N. Suzuki , H. Izawa , M. Morimoto , H. Saimoto
      Surface N-maleylation and N-naphthaloylation of chitin nanofiber (NF) were achieved by reaction with maleic and naphthalic anhydrides in water, respectively. Maleyl and naphthaloyl groups were sufficiently introduced to an amino group on a surface-deacetylated chitin NF. The characteristic nanofiber morphology was maintained after maleylation and naphthaloylation. These NFs were homogeneously dispersed in several organic solvents. Especially, naphthaloyl chitin NF was dispersed even in aromatic solvents, owing to the high level of solvation interactions with the naphthaloyl group. The NF dispersions in those aromatic solvents exhibited a dispersive-to-precipitate transition response at approximately 29°C. Moreover, the naphthaloyl chitin NF dispersion cut harmful ultraviolet light. The maleyl chitin NF formed a self-standing gel after cross-linking polymerization.


      PubDate: 2014-12-20T11:29:02Z
       
  • Preparation and application of starch nanoparticles for nanocomposites: A
           review
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): Déborah Le Corre , Hélène Angellier-Coussy
      The increasing scientific and industrial interest for starch nanoparticles (SNP) has led to the development of numerous methods for preparing sub-micron starch fillers for nanocomposites applications. Starch nanocrystals (SNC), which constitute the focus of this review, are one type of SNP with crystalline property and platelet like morphology. SNC can be extracted from various starch botanical sources, allowing to obtain a large range of amylose content, shape, viscosity in suspension, surface reactivity and thermal resistance. To date, the most common method for extracting SNC remains the mild acid hydrolysis of the amorphous parts of native granular starch. So far, alternative methods render much lower yield. Since first publications on SNC, the principal aim is to use them as reinforcement in polymer matrices. Thanks to the reactive nature of starch, SNC surface can be modified by grafting or cross-linking which renders them more readily dispersible in the polymer matrix. The present review focus on the reinforcing effect and mechanisms of SNC, as well as on their impact of barrier properties of polymers.


      PubDate: 2014-12-20T11:29:02Z
       
  • A review on lignin-based polymeric, micro- and nano-structured materials
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): Antoine Duval , Martin Lawoko
      Next to cellulose, lignin is the second most abundant biopolymer, and the main source of aromatic structures on earth. It is a phenolic macromolecule, with a complex structure which considerably varies depending on the plant species and the isolation process. Lignin has long been obtained as a by-product of cellulose in the paper pulp production, but had rather low added-value applications. Changes in the paper market have however stimulated the need to focus on other applications for lignins. In addition, the emergence of biorefinery projects to develop biofuels, bio-based materials and chemicals from carbohydrate polymers should also generate large amounts of lignin with the potential for value addition. These developments have brought about renewed interest in the last decade for lignin and its potential use in polymer materials. This review covers both the topics of the direct use of lignin in polymer applications, and of the chemical modifications of lignin, in a polymer chemistry perspective. The future trend toward micro- and nanostructured lignin-based materials is then addressed.


      PubDate: 2014-12-20T11:29:02Z
       
  • Alternate and random (co)polymers composed of anthracene and
           chloromethylstyrene units through controlled radical ring-opening
           
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Kazuhiro Nakabayashi , Ayumi Tsuda , Hiroshi Otani , Hideharu Mori
      A cyclic monomer containing the chloromethyl unit 10-methylene-9,10-dihydroanthryl-9-spiro(4′-chloromethylphenyl)cyclopropane (MDCMS) was polymerized using a controlled radical ring-opening polymerization via a reversible addition-fragmentation chain transfer (RAFT) process to afford a nonconjugated alternate polymer composed of anthracene and chloromethylstyrene (CMS) units. Well-defined random copolymers were obtained through the ring-opening RAFT copolymerization. Various functional groups were incorporated into the alternate polymer. The alternate polymer containing imidazole rings exhibited fluorescence quenching as a result of charge transfer. Fluorescence resonance energy transfer (FRET) was observed in the alternate polymers containing naphthalene and thiophene rings. The random copolymers obtained by copolymerization followed by post-functionalizations exhibited characteristic optoelectronic properties that differed from those of the alternate polymers.


      PubDate: 2014-12-20T11:29:02Z
       
  • Functionalized electrospun regenerated cellulose fibers for immobilizing
           pyranose 2-oxidase
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Weerapha Panatdasirisuk , Thammasit Vongsetskul , Jeerus Sucharitakul , Pimchai Chaiyen , Pramuan Tangboriboonrat
      This work aims to reuse pyranose 2-oxidase (P2O) and improve its thermal stability compared to the wild-type enzyme by immobilizing onto regenerated cellulose fibers (RC). The P2O-immobilized RC fibers (P2O-RC) showed the improvement in terms of thermal stability. Cellulose acetate (CA) fibers (229±42nm) were electrospun from 17% w/w CA (MW ∼3×104 g/mol) with 5% w/w Tween 80 dissolved in a mixture of water (25% w/w) and acetic acid (75% w/w) at an applied voltage of 25kV and a fiber collection distance of 10cm. Then, the fiber surface was treated with 0.5M potassium hydroxide in ethanol and 12% w/v glutaraldehyde using aluminum sulfate hexadecahydrate as a catalyst before P2O was immobilized on the treated fibers. Effects of the immobilization process on thermal and pH stability of P2O were investigated by measuring P2O activity based on peroxidase coupled assay. Results indicated that P2O-RC catalyzed the oxidation of glucose at high temperatures (60 and 70°C) better than the free enzyme did. Therefore, P2O-RC are potentially useful as a heterogeneous catalyst under the conditions that P2O cannot endure.


      PubDate: 2014-12-20T11:29:02Z
       
  • Cellulose nanopapers as tight aqueous ultra-filtration membranes
    • Abstract: Publication date: Available online 11 October 2014
      Source:Reactive and Functional Polymers
      Author(s): Andreas Mautner , Koon-Yang Lee , Tekla Tammelin , Aji P. Mathew , Alisyn J. Nedoma , Kang Li , Alexander Bismarck
      Recently, we have demonstrated the use of wood-derived nanocellulose papers, herein termed nanopapers, for organic solvent nanofiltration applications. In this study, we extend the use of these nanopapers to tight ultrafiltration (UF) membranes. The feasibility of such nanopaper-based UF membranes intended for use in water purification is shown. Four types of nanocelluloses, namely bacterial cellulose, wood-derived nanocellulose, TEMPO-oxidized cellulose nanofibrils and cellulose nanocrystals, were used as raw materials for the production of these nanopaper-based membranes. The resulting nanopapers exhibit a transmembrane permeance in the range of commercially available tight UF membranes with molecular weight cut-offs ranging from 6 to 25kDa, which depends on the type of nanocellulose used. These molecular weight cut-offs correspond to average pore sizes of a few nanometres. The rejection performance of the nanopapers is on the border of nanofiltration and UF. We demonstrate that the pore size of the nanopapers can be controlled by using different types of nanocellulose fibrils.


      PubDate: 2014-12-20T11:29:02Z
       
  • Impact of preparation method on physical properties and gas separation
           performance of fluorinated copolymer membranes
    • Abstract: Publication date: Available online 22 October 2014
      Source:Reactive and Functional Polymers
      Author(s): Soon-Chien Lu , Ivo F.J. Vankelecom
      Two batches of poly(vinylidene fluoride–hexafluoropropylene) [P(VDF–HFP)] copolymer with different monomer ratios were thoroughly characterised and cast into membranes to relate the fundamental properties of this copolymer with its performance in CO2 separation. Solubility testing revealed that the PVDF part of the copolymer was dominating and calculations with Hansen’s solubility parameters corroborated the outcome. A very slow solvent evaporation rate and use of solvents with a high boiling point were found to be essential in the formation of defect-free membranes from this copolymer for gas separations. Physical examination, DSC, XRD and TGA were also performed to better link the fundamental membrane properties to the gas separation performance. A low crystallinity in the prepared P(VDF–HFP) membranes was favourable in terms of compatibility, solubility, membrane formation and CO2 separations.


      PubDate: 2014-12-20T11:29:02Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85




      PubDate: 2014-12-20T11:29:02Z
       
  • Renewable nanomaterials, polymers and composites
    • Abstract: Publication date: December 2014
      Source:Reactive and Functional Polymers, Volume 85
      Author(s): Lars Berglund , Alexander Bismarck , Alain Dufresne , Akira Isogai



      PubDate: 2014-12-20T11:29:02Z
       
  • An emerging approach for the targeting analysis of dimethoate in olive
           oil: The role of molecularly imprinted polymers based on photo-iniferter
           induced “living” radical polymerization
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Nuno Martins , Elisabete P. Carreiro , Marco Simões , Maria João Cabrita , Anthony J. Burke , Raquel Garcia
      This study concerns the first attempt to prepare molecularly imprinted polymers for the selective recognition of dimethoate using an iniferter polymerization technique (Inif-MIP). The synthesized polymers were fully characterized. SEM micrographs show a large accessibility to the binding sites with a significant improvement in MIP morphology. Inif-MIPs displayed high adsorption capacity (Q =5.3mgg−1). The selectivity of this imprinting system was also assessed by means of cross-selectivity assays and the results obtained show that Inif-MIP displays a high selectivity for dimethoate, whereas some structural analogues (omethoate, malathion and methidathion) are poorly retained (6.3–28.7%) or not retained at all (fenthion). Inif-MISPE methodology was implemented by packing Inif-MIPs particles into a Solid Phase Extraction (SPE) cartridge and the loading, washing and eluting steps were optimized. The suitability of this sample preparation technique was demonstrated, as concentrations of dimethoate close to the tolerated maximum residue limits in the olive oil samples could be satisfactorily analyzed with good precision and accuracy. Some remarkable characteristics, like the sorbent reusability (at least 20 cycles without the lost of selectivity), low solvent consumption, reduced sample handling and, moreover higher recovery rates reaching 88% could be ascribed to the Inif-MISPE methodology.


      PubDate: 2014-12-20T11:29:02Z
       
  • Dual-responsive polymer–drug nanoparticles for drug delivery
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Mong Liang , Tsung-Min Yang , Hui-Ping Chang , Yu-Min Wang
      A well-defined, dual temperature- and pH-responsive drug carrier was synthesized through the radical copolymerization of methacrylic acid, N-isopropylacrylamide, and an N-(methacryloyl)glycylglycine 4-nitrophenyl ester. When the anticancer agent gemcitabine or antibiotic sulfamethoxazole was conjugated with a polymer and heated beyond its low critical solution temperature (40°C), a dual temperature- and pH-induced phase transition was observed. This temperature was considered ideal for activating drug aggregation under hyperthermic and acidic conditions. The structure and properties of polymer drugs were investigated using nuclear magnetic resonance, Fourier transform infrared spectrometry, ultraviolet–visible absorption, transmission electron microscopy, and gel permeation chromatography. At a critical micelle concentration of 1mg/mL, both polymer drugs formed micellar structures with diameters ranging from 50nm to 150nm, based on TEM image. These micelles exhibited higher pharmacological efficacy than the free drug alone did, and the cytotoxicity at the target site was substantially enhanced compared with that of the polymer–drug conjugate formed under normal physiological conditions.


      PubDate: 2014-12-20T11:29:02Z
       
  • Towards continuous junction (CJ) organic electronic devices: Fast and
           clean post-polymerization modification by oxidation using
           dimethyldioxirane (DMDO)
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Florian Glöcklhofer , Daniel Lumpi , Markus Kohlstädt , Olena Yurchenko , Uli Würfel , Johannes Fröhlich
      An advanced design concept for organic electronic devices relying on functional polymers is presented. The concept aims at realizing a gradual transition from an electron-donating to an electron-accepting material in a specific post-polymerization modification step. Hence, this approach facilitates a straight forward fabrication compared to conventional multi-layer architectures. The synthesis via microwave-assisted Cu(I)-catalyzed azide–alkyne cycloaddition of the reactive polymers based on sulfur, selenium and tellurium as active sites is presented; full characterization of model compounds and polymers is provided. Additionally, a reliable procedure for post-polymerization oxidation applying dimethyldioxirane is developed. Photophysical and electrochemical characteristics of the novel polymers reveal the feasibility but also the challenges of the continuous junction concept.


      PubDate: 2014-12-20T11:29:02Z
       
  • Chemically modified organic/inorganic nanoporous composite particles for
           the adsorption of reactive black 5 from aqueous solution
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Ali Nematollahzadeh , Akbar Shojaei , Mehdi Karimi
      In the present work, we report a chemically modified polyacrylamide/silica nanoporous composite adsorbent for the removal of reactive black 5 (RB5) azo dye from aqueous solutions. The composite adsorbent was synthesized in a packed bed and modified by ethylenediamine (EDA). The adsorbent was characterized by Fourier transformation infrared (FT-IR), thermogravimetric analysis (TGA), thermoporometry, Brunauer, Emmett and Teller (BET) method and scanning electron microscopy (SEM). Mechanical stability of the adsorbent was examined in a packed bed by following the back-pressure of the column. Pore diameter of the composite adsorbent in dry and wet states was estimated to be about 18.71nm and 12.61nm, respectively. Adsorption experiments were performed in batch mode and effect of various operational parameters on the adsorption capability of the adsorbent was studied systematically. The maximum adsorption capacity of the modified composites was found to be 454.5mg RB5/g of adsorbent. The equilibrium data were analyzed by Langmuir, Freundlich, Sips, BET and Redlich–Peterson isotherm models and found to fit well to the BET isotherm. The data kinetically followed the pseudo-second-order model. High adsorption capacity, fast removal mechanism, and good mechanical stability are three advantages of the presented composite for the removal of RB5.


      PubDate: 2014-12-20T11:29:02Z
       
  • Preparation of cellulose-based conductive hydrogels with ionic liquid
    • Abstract: Publication date: January 2015
      Source:Reactive and Functional Polymers, Volume 86
      Author(s): Xiangtao Liang , Bing Qu , Junrong Li , Huining Xiao , Beihai He , Liying Qian
      Conductive hydrogel composed of microcrystalline cellulose (MCC) and polypyrrole (PPy) was prepared in ionic liquid; and the resulting hydrogel was characterized with FT-IR, SEM, XRD and TGA. By doping with TsONa, the MCC/PPy composite hydrogels showed relatively high electrical conductivity, up to 7.83×10− 3 S/cm, measured using a four-probe method. The swelling kinetics of the composite hydrogels indicated that the swelling process was mainly influenced by the cellulose content; and the equilibrium swelling ratio decreased as the increasing of MCC content in the hydrogels. In addition, the MCC/PPy composite hydrogels exhibited significantly enhanced mechanical property in contrast to MCC hydrogel.


      PubDate: 2014-12-20T11:29:02Z
       
  • Quantification of singlet oxygen generation from photodynamic hydrogels
    • Abstract: Publication date: Available online 6 December 2014
      Source:Reactive and Functional Polymers
      Author(s): Rebecca A. Craig , Colin P. McCoy , Áine T. De Baróid , Gavin P. Andrews , Sean P. Gorman , David S. Jones
      Recently, we described a series of novel porphyrin-impregnated hydrogels capable of producing microbicidal singlet oxygen (1O2) on photoactivation. Indirect assessment of the efficacy of 1O2 production from such hydrogels has been previously described using microbiological techniques, but here we report a novel, direct method of quantification. Anthracene-9,10-dipropionic acid (ADPA) is known to irreversibly form an endoperoxide on reaction with 1O2, causing photobleaching of its absorbance band at approximately 378 nm. Here, the reaction of this probe is exploited in a novel way to provide a simple, inexpensive, and convenient measurement of 1O2 generation from the surface of porphyrin-incorporated photosensitising hydrogels, with the ability to account for effects due to hydrogel porosity. Ingress of the probe into the materials was observed, with rates of up to 3.83 x 103 s-1. This varied by up to 200-fold with material composition and surface modification. Rates of 1O2 generation in these porphyrin-incorporated hydrogels, after compensating for ADPA ingress, ranged from 1.86x103 – 5.86x103 s-1. This work demonstrates a simple and straightforward method for direct 1O2 quantification from porous materials, with general utility.


      PubDate: 2014-12-20T11:29:02Z
       
 
 
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